Microenvironment engineering for guiding spatially and epitaxially uniform lithium plating in lithium metal batteries

The manipulation of plated lithium morphology is the crucial for extending the cycle life of lithium metal batteries. Dendritic growth, a major concern, is influenced by the microenvironment of lithium plating, including the curvature of lithium-ion transfer path, as well as the inner space and surface chemistry of the separator and scaffold. In this study, we report a novel separator-interface-scaffold microenvironment for practical lithium metal batteries (LMBs), in which surface chemistry of scaffold and separator are tuned to create a transmission path with low curvature and induce spatially and epitaxial lithium plating. With such an elaborate design, the resulting LMB demonstrates exceptional stability, exhibiting dendrite-free cycling for 5542 h with a low voltage hysteresis of 13 mV at 5 mA cm⁻²/5 mAh cm⁻². It also demonstrates stable cycling for 500 h under ultrahigh currents of 50 mA cm⁻² and deep plating/stripping up to 20 mAh cm⁻². Notably, a remarkable cumulative plating capacity of 13,855 mAh cm⁻² is achieved. The full cells paired with commercial cathodes with high loading mass delivered remarkably improved rate and cycling stability performance. This study highlights the critical role of the plating microenvironment in enhancing LMBs for high-energy storage devices.